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Abstract:

The invention is directed to a method for making small crystal zeolites,
such as small crystal SSZ-32, in the absence of an amine component.

Claims:

1. A method of making a small crystal zeolite, comprising (a) preparing a
reaction mixture comprising: (i) at least one active source of an oxide
of silicon; (ii) at least one active source of an oxide of aluminum;
(iii) at least one active source of an alkali metal; (iv) hydroxide ions;
and (v) an organic templating agent having the structure: ##STR00003##
wherein R is a C1 to C5 alkyl group and A.sup.- is an anion
which is not detrimental to the crystallization of the zeolite; and (b)
maintaining the reaction mixture under conditions sufficient to form
crystals of the zeolite wherein the zeolite is prepared in the absence of
an amine component.

7. The method of claim 1, wherein the conditions sufficient to form
crystals of the zeolite comprises heating the reaction mixture at a first
temperature of from 175.degree. C. to 190.degree. C. for a period of from
12 to 48 hours; and reducing the first temperature of the reaction
mixture to a second temperature of from 140.degree. C. to 170.degree. C.
for a suitable period of time to form crystals of the zeolite.

8. The method of claim 1, wherein the zeolite has, in its as-synthesized
form, a silica to alumina molar ratio of 20 to less than 40.

9. The method of claim 1, wherein the zeolite has a crystallite size of
10 to 40 nanometers.

10. The method of claim 1, wherein the zeolite has a crystallite size of
12 to 20 nanometers.

12. The method of claim 1 further comprising monitoring at least one
viscometric parameter of the reaction mixture; and determining an
endpoint.

13. The method of claim 12, the at least one viscometric parameter of the
reaction mixture is selected from the group consisting of viscosity shear
rate index, measured viscosity, or combination thereof.

14. The method of claim 12, wherein the endpoint is determined based on a
change in measured viscosity of the reaction mixture, a change in pH of
the reaction mixture, or combination thereof.

Description:

TECHNICAL FIELD

[0001] The invention relates generally to a method of making a catalyst
comprising a small crystal intermediate pore size zeolite, specifically
SSZ-32.

BACKGROUND

[0002] Small crystal SSZ-32 (hereinafter referred to as SSZ-32X), in
comparison with standard SSZ-32, possesses less defined crystallinity,
altered Argon adsorption ratios, increased external surface area and
reduced cracking activity over other intermediate pore size molecular
sieves used for a variety of catalytic processes. SSZ-32X and methods for
making it are disclosed in U.S. Pat. Nos. 7,390,763 and 7,569,507. Both
methods require the combination of an imidazolium cation and an amine
component as templates.

[0003] There is a need for improved methods for preparing SSZ-32X.

SUMMARY OF THE INVENTION

[0004] In one aspect, the invention relates to a method for making a small
crystal zeolite, comprising preparing a reaction mixture comprising: at
least one active source of an oxide of silicon, at least one active
source of an oxide of aluminum, at least one active source of an alkali
metal, hydroxide ions, and a organic templating agent having the
structure:

##STR00001##

wherein R is a C1 to C5 alkyl group and A.sup.- is an anion
which is not detrimental to the crystallization of the zeolite; and
maintaining the reaction mixture under conditions sufficient to form
crystals of the zeolite wherein the zeolite is prepared in the absence of
an amine component.

BRIEF DESCRIPTION OF THE FIGURES

[0005] FIG. 1 illustrates changes in apparent viscosity and pH of slurry
samples at various shear rates taken from the autoclave during a zeolite
synthesis.

[0007] The following terms will be used throughout the specification and
will have the following meanings unless otherwise indicated.

[0008] The term "small crystal zeolite" refers to zeolites having a
crystallite size of no more than 100 nanometers.

[0009] The term "crystallite size" refers to the longest dimension of the
crystal. The crystallite, size of the zeolite may be determined by, for
example, grinding the shaped particles to separate the individual
crystals. High resolution electron micrographs of the separated crystals
can then be prepared, after which the average size of individual zeolite
crystals can be determined by reference to calibrated length standards.
An average crystallite size may then be computed in various well-known
ways. It is important to note that for purposes of this invention,
zeolite crystallite size is distinguished from what some manufacturers
term "zeolite particle size," the latter being the average size of all
particles, including both individual crystals and polycrystalline
agglomerates, in the as-produced zeolite powder.

[0010] The term "active source" refers to a reagent or precursor material
capable of supplying an element in a form that can react and be
incorporated into the target zeolite structure. The term "source" and
"active source" are used interchangeably herein.

[0011] The term "reaction time" refers to the elapsed time from a point
when the reaction mixture has attained the designated or target reaction
temperature; for example, for a reaction mixture having an eight-hour
ramp from ambient to reaction temperature, the end of the eight-hour ramp
period represents reaction time zero. The terms "reaction time" and "time
on stream" may be used herein interchangeably and synonymously.

[0012] The term "measured viscosity" refers to a value for the viscosity
of a fluid such as a reaction mixture for zeolite synthesis as recorded,
determined or measured, for example, using an instrument such as a
rheometer. The measured viscosity of a sample removed from the reaction
mixture at a given time point may be different from the actual viscosity
of the reaction mixture in situ at that time point due, for example, to
differences in the dynamics of crystallite aggregation and disaggregation
in a reactor and in a sample removed from the reactor. Nonetheless,
changes over time of measured viscosity of samples of the reaction
mixture have been found by the applicant to have predictive value in
determining the endpoint of the zeolite synthesis. The terms "measured
viscosity" and "apparent viscosity" may be used herein interchangeably
and synonymously.

[0013] The term "endpoint" refers to the stage of the reaction or process
when the target product has been formed and has attained at least one
desired product characteristic or attribute, for example, in terms of
crystal size, physical properties, catalytic activity, yield, and the
like. For a given product and synthesis process, the endpoint may vary
depending on the desired product attribute(s) in relation to the intended
use(s) for the product.

Zeolite Synthesis

[0014] SSZ-32X zeolites can be suitably prepared, in the absence of an
amine component, from an aqueous solution containing sources of an alkali
metal oxide or hydroxide, an imidazolium cation which is subsequently
ion-exchanged to the hydroxide form, an oxide of aluminum (preferably
wherein the aluminum oxide source provides aluminum oxide which is
covalently dispersed on silica), and an oxide of silicon. The reaction
mixture should have a composition in terms of molar ratios falling within
the following ranges:

[0017] In one embodiment, the at least one active source of an oxide of
silicon and the at least one active source of an oxide of aluminum are
derived from a common source. An exemplary common source is an
alumina-coated silica sol, such as 1SJ612, which is available
commercially from Nalco (Naperville, Ill.). In another approach, zeolites
of pentasil structure and lower silica/alumina ratios (approximately 10)
can be used as feedstocks for the synthesis of zeolite SSZ-32X. An
advantage of employing a common source for the alumina and silica is the
elimination of the gel formation step, wherein the sources of silicon and
aluminum are stirred until a homogeneous mixture is obtained, which
consequently reduces zeolite preparation time.

[0018] Generally, the at least one active source of an oxide of silicon,
the at least one active source of an oxide of aluminum, the at least one
active source of an alkali metal, hydroxide ions and the organic
templating agent are added to deionized water to form the reaction
mixture. In one embodiment, the components are mixed in the absence of
deionized water solvent to provide a more concentrated reaction mixture.
In one embodiment, the reaction mixture has a H2O/SiO2 molar
ratio of from 15 to 20.

[0019] M is an alkali metal cation, preferably sodium or potassium. Any
alkali metal-containing compound which is not detrimental to the
crystallization process is suitable. Sources for the alkali metal ions
include alkali metal oxides, hydroxides, nitrates, sulfates, halogenides,
oxalates, citrates and acetates. The organic templating agent (O) which
acts as a source of the quaternary ammonium-ion employed can provide
hydroxide ion.

[0020] Q is an organic templating agent having the structure

##STR00002##

wherein R is a C1 to C5 alkyl group and A.sup.- is an anion
that is not detrimental to the formation of the zeolite. Examples of
C1 to C5 alkyl groups include methyl, ethyl, n-propyl,
isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl and
neopentyl. In one embodiment, R is methyl; in another embodiment, R is
isopropyl. Representative examples of anions include hydroxide, acetate,
sulfate, carboxylate and halogens, for example, fluoride, chloride,
bromide and iodide. In one embodiment, the anion is hydroxide. U.S. Pat.
Nos. 5,053,373 and 5,252,527 disclose a zeolite such as SSZ-32 which is
prepared using an imidazolium cation as an organic templating agent.

[0021] Salts, particularly alkali metal halides such as sodium chloride,
can be added to or formed in the reaction mixture. They are disclosed in
the literature as aiding the crystallization of zeolites while preventing
silica occlusion in the lattice.

[0022] The reaction mixture is maintained at an elevated temperature until
the crystals of the zeolite are formed. The temperatures during the
hydrothermal crystallization step are generally maintained from
140° C. to 200° C., more typically from 160° C. to
190° C., and often from 170° C. to 180° C. In one
embodiment, the conditions sufficient to form crystals of the zeolite
comprises heating the reaction mixture at a first temperature of from
175° C. to 190° C. for a period of from 12 to 48 hours; and
reducing the first temperature of the reaction mixture to a second
temperature of from 140° C. to 170° C. for a suitable
period of time to form crystals of the zeolite. The crystallization
period is generally greater than 1 day and more typically from 2 days to
10 days.

[0023] The hydrothermal crystallization is conducted under pressure and
usually in an autoclave so that the reaction mixture is subject to
autogenous pressure. The reaction mixture can be stirred while components
are added as well as during crystallization. During the hydrothermal
crystallization step, the crystals can be allowed to nucleate
spontaneously from the reaction mixture. The reaction mixture can also be
seeded with SSZ-32X crystals both to direct, and to accelerate the
crystallization, as well as to minimize the formation of undesired
aluminosilicate contaminants. In one embodiment, seeds are present in the
reaction mixture in an amount of 0.5 to 10 wt. % wherein the weight
percent (wt. %) of the seed is based on the weight percent of SiO2;
in another embodiment, seeds are present in an amount of 1 to 5 wt. %.

[0024] In one embodiment, the method of making a small crystal zeolite
further comprises monitoring at least one viscometric parameter of the
reaction mixture and determining an endpoint of the zeolite synthesis
process. During the reaction, the extent of crystallization may be
monitored by measuring, at various time points, at least one viscometric
parameter of the reaction mixture. It has been found that during
crystallization, certain bulk properties of the reaction mixture vary
concurrently with the progression of the synthesis process, thereby
permitting the measurement of the reaction mixture bulk properties to
form a basis for determining the status of one or more properties of the
zeolite. Such properties may include the crystallization status of the
reaction mixture (crystallite size, degree of crystallite agglomeration)
as well as the quantitative product yield, and characteristics related to
the catalytic activity of the zeolite.

[0025] In one embodiment, the monitoring step comprises periodically
removing a sample of the reaction mixture, cooling each sample to a
pre-defined temperature, and measuring the at least one viscosity
parameter of each sample. The frequency at which the reaction mixture is
sampled may be hourly or at a greater or lesser frequency. For example,
samples may be withdrawn from the reactor at a frequency of once every 10
minutes to 120 minutes, and typically once every 15 minutes to 60
minutes. The cooling of each sample to a pre-defined temperature may be
generally in the range from 5° C. to 50° C., typically from
10° C. to 30° C., and often from 15° C. to
25° C. Generally, the viscometric parameter of each sample is
measured within ±0.2° C. of the p' re-defined temperature,
typically within ±0.1° C., and often within ±0.05° C.
of the pre-defined temperature. Thereafter, an endpoint of the molecular
sieve synthesis process may be determined based, for example, on a change
in the at least one viscosity parameter of the reaction mixture.

[0026] In one embodiment, the at least one viscometric parameter of the
reaction mixture is selected from the group consisting of viscosity shear
rate index, measured viscosity, or combination thereof.

[0027] The viscosity shear rate index of each sample of the reaction
mixture can be quantified or determined by subjecting the sample to a
plurality of shear rates at the pre-defined temperature, and recording a
shear stress value corresponding to each of the plurality of shear rates
to provide a plurality of shear stress values. Typically, each of the
plurality of shear rates may be within the range from 100 s-1 to
1000 s-1. Thereafter, the viscosity shear rate index (η) for the
sample can be determined based on the plurality of shear rates and the
corresponding plurality of shear stress values, wherein the relationship
between shear rate (γ) and shear stress (σ) is given by:
σαγ.sup.η. As an example, the viscosity shear rate
index (η) can be determined by fitting a straight line to a plot of
the natural log of the shear stress values (ln(σ), Pascals; y-axis)
versus the natural log of the shear rate values (ln(γ), s-1;
x-axis). Using this model, Newtonian fluids have η=1, whereas fluids
(reaction mix slurries) with weakly agglomerated crystallites, will
typically exhibit pseudo-plastic (or shear-thinning) behavior with
η<1. In general, the smaller the viscosity shear rate index of a
slurry, the greater its degree of pseudo-plasticity.

[0028] The measured viscosity can be determined for each of a plurality of
samples of the reaction mixture taken at a plurality of points in time
during the zeolite synthesis process. The measured viscosity of each
sample may be determined via a rheometer by subjecting the sample to at
least one shear rate at the pre-defined temperature, and recording at
least one shear stress corresponding to the at least one shear rate.
Thereafter, the measured viscosity (μ) of the sample may be determined
by dividing the shear stress (a) by the corresponding shear rate (y),
namely, μ=a/y. Typically, the at least one shear rate to which the
sample is subjected may be in the range from 100 s-1 to 1000
s-1.

[0029] The pH of the reaction mixture may also be monitored during
crystallization, for example, to provide supplemental data for
determining or confirming the status of one or more properties of the
zeolite. The use of pH measurements to monitor crystallization is known
in the art. See, for example, J. L. Casci et al., Zeolites, 3, 186-187
(1983); B. M. Lowe, Zeolites, 3, 300-305 (1983); S. I. Zones, Zeolites,
9, 458-467 (1989); and S. I. Zones et al., Microporous Mesoporous Mater.,
58, 263-277 (2003). One advantage of the method of the present invention
is that zeolites are prepared in the absence of an amine component.
Previously disclosed methods required the presence an amine component
which may act as a potential buffer. Removal of the amine component
permits the changes associated with crystallization to be better followed
by pH, thereby allowing the reaction to be quenched with greater
accuracy.

[0030] Accordingly, various properties of the reaction mixture, such as
viscometric parameters, may be used to monitor the progress of
crystallization of the target zeolite and to determine or predict the
reaction endpoint. The endpoint of the synthesis process may be
determined based on a change in measured viscosity of the reaction
mixture, a change in pH of the reaction mixture, or combination thereof.
FIG. 1 illustrates the changes in apparent viscosity and pH of slurry
samples as an SSZ-32X crystallization progresses to an endpoint of about
65 hours. Moreover, monitoring the progress of crystallization allows for
obtaining higher yields of zeolites of the desired crystallite size and
less of undesirable crystallite sizes (either under-crystallized or
over-crystallized products).

[0031] Accordingly, during synthesis at least one property of the zeolite,
for example, crystal size or yield, is estimated by comparing one or more
values of a measured parameter of the reaction mixture with data from a
predetermined relationship between the zeolite property and the measured
property. The predetermined relationship between the zeolite property and
the measured property is derived from one or more previous synthesis
processes, for example, using the same or substantially the same
equipment, and the same or substantially the same reaction mixture and
conditions, during which at least one measured property and at least one
of the properties of the sieve were correlated as a function of time.
Thus, once the system has been calibrated by correlating measured
reaction mixture properties with observed zeolite properties, the
measured reaction mixture properties may serve as a basis for determining
the progress of the reaction, with respect to one or more properties of
the zeolite, during subsequent syntheses.

[0032] Once the desired zeolite crystals have formed, the solid product is
separated from the reaction mixture by standard mechanical separation
techniques such as filtration or centrifugation. The crystals are
water-washed and then dried, for example, at 90° C. to 150°
C. for from 8 to 24 hours, to obtain the as-synthesized, zeolite
crystals. The drying step can be performed at, or below, atmospheric
pressure.

[0033] In one embodiment, the zeolite of the invention has a crystallite
size of 10 to 40 nanometers; in another embodiment, a crystallite size of
12 to 20 nanometers.

[0034] In one embodiment, the zeolite of the invention has, in its
as-synthesized form, a silica to alumina molar ratio of 20 to less than
72; in another embodiment, a silica to alumina molar ratio of 20 to less
than 40.

[0035] Standard SSZ-32 and SSZ-32X have the framework topology designated
"MTT" by the International Zeolite Association. SSZ-32X zeolites
synthesized according to the present invention may be characterized by
their X-ray diffraction (XRD) pattern. Standard SSZ-32 and SSZ-32X may be
distinguished by XRD because the XRD pattern broadens as the crystallites
are reduced in size. FIG. 2 compares the SSZ-32X peak occurrence and
relative intensity with that of standard SSZ-32. The powder XRD lines of
Table 2 are representative of calcined standard SSZ-32. The powder XRD
lines of Table 3 are representative of calcined SSZ-32X made in
accordance with this invention.

[0036] Minor variations in the diffraction pattern can result from
variations in the mole ratios of the framework species of the particular
sample due to changes in lattice constants. In addition, sufficiently
small crystals will affect the shape and intensity of peaks, leading to
significant peak broadening. Minor variations in the diffraction pattern
can also result from variations in the organic templating agent used in
the preparation and from variations in the Si/Al molar ratio of various
preparations. Calcination can also cause minor shifts in the XRD pattern.
Notwithstanding these minor perturbations, the basic crystal lattice
structure remains unchanged.

[0037] The powder X-ray diffraction patterns presented herein were
collected by standard techniques. The radiation was CuK-α
radiation. The peak heights and the positions, as a function of 2θ
where θ is the Bragg angle, were read from the relative intensities
of the peaks (adjusting for background), and d, the interplanar spacing
in Angstroms corresponding to the recorded lines, can be calculated.

[0038] SSZ-32X can be used as-synthesized or can be thermally treated
(calcined). Usually, it is desirable to remove the alkali metal cation by
ion exchange and replace it with hydrogen, ammonium, or any desired metal
ion. The zeolite can be leached with chelating agents, for example, EDTA
or dilute acid solutions, to increase the silica alumina mole ratio.
SSZ-32X can also be steamed. Steaming helps stabilize the crystalline
lattice to attack from acids.

[0039] The zeolite can also be impregnated with the metals, or, the metals
can be physically intimately admixed with SSZ-32X using standard methods
known to the art. And, the metals can be occluded in the crystal lattice
by having the desired metals present as ions in the reaction mixture from
which the SSZ-32X zeolite is prepared.

[0040] Typical ion exchange techniques involve contacting the SSZ-32X with
a solution containing a salt of the desired replacing cation or cations.
Although a wide variety of salts can be employed, chlorides and other
halides, nitrates, and sulfates are particularly preferred.
Representative ion exchange techniques are disclosed in a wide variety of
patents including U.S. Pat. Nos. 3,140,249; 3,140,251; and 3,140,253. Ion
exchange can take place either before or after SSZ-32X is calcined.

[0041] Following contact with the salt solution of the desired replacing
cation, SSZ-32X is typically washed with water and dried at temperatures
ranging from 65° C. to 315° C. After washing, SSZ-32X can
be calcined in air or inert gas at temperatures ranging from 200°
C. to 820° C. for periods of time ranging from 1 to 48 hours, or
more, to produce a catalytically active product especially useful in
hydrocarbon conversion processes.

[0042] The SSZ-32X zeolite described above may be converted to its acidic
form and then may be mixed with a refractory inorganic oxide carrier
precursor and an aqueous solution to form a mixture. The aqueous solution
is preferably acidic. The solution acts as a peptizing agent. The carrier
(also known as a matrix or binder) may be chosen for being resistant to
the temperatures and other conditions employed in organic conversion
processes. Such matrix materials include active and inactive materials
and synthetic or naturally occurring zeolites as well as inorganic
materials such as clays, silica and metal oxides. The latter may occur
naturally or may be in the form of gelatinous precipitates, sols, or
gels, including mixtures of silica and metal oxides. Use of an active
material in conjunction with the synthetic SSZ-32X, that is, combined
with it, tends to improve the conversion and selectivity of the catalyst
in certain organic conversion processes.

[0043] SSZ-32X may be commonly composited with porous matrix materials and
mixtures of matrix materials such as silica, alumina, titania, magnesia,
silica-alumina, silica-magnesia, silica-zirconia, silica-thoria,
silica-beryllia, silica-titania, titania-zirconia as well as ternary
compositions such as silica-alumina-thoria, silica-alumina-zirconia,
silica-alumina-magnesia and silica-magnesia-zirconia. The matrix can be
in the form of a co-gel. The preferred matrix materials are alumina and
silica. It is possible to add metals for the enhancement of catalytic
performance, during the actual synthesis of SSZ-32X, as well as during
later steps in catalyst preparation. Methods of preparation include solid
state ion exchange which is achieved by thermal means, spray drying with
a metal salt solution, and preparation of a slurry in a salt solution.
The slurry may be filtered to retrieve the SSZ-32X, now loaded with
metal.

[0044] Inactive materials can suitably serve as diluents to control the
amount of conversion in a given process so that products can be obtained
economically without using other means for controlling the rate of
reaction. Frequently, zeolite materials have been incorporated into
naturally occurring clays, for example, bentonite and kaolin. These
materials for example clays, oxides, etc., function, in part, as binders
for the catalyst. It is desirable to provide a catalyst having good crush
strength, because in petroleum refining the catalyst is often subjected
to rough handling. This tends to break the catalyst down into powders
which cause problems in processing.

[0045] Naturally occurring clays which can be composited with the
synthetic SSZ-32X of this invention include the montmorillonite and
kaolin families, which families include the sub-bentonites and the
kaolins commonly known as Dixie, McNamee, Georgia and Florida clays or
others in which the main mineral constituent is halloysite, kaolinite,
dickite, nacrite, or anauxite. Fibrous clays such as sepiolite and
attapulgite can also be used as supports. Such clays can be used in the
raw state as originally mined or can be initially subjected to
calcination, acid treatment or chemical modification.

[0046] The mixture of SSZ-32X and binder can be formed into a wide variety
of physical shapes. Generally speaking, the mixture can be in the form of
a powder, a granule, or a molded product, such as an extrudate having a
particle size sufficient to pass through a 2.5-mesh (Tyler) screen and be
retained on a 48-mesh (Tyler) screen. In cases where the catalyst is
molded, such as by extrusion with an organic binder, the mixture can be
extruded before drying, or dried or partially dried and then extruded.
The dried extrudate is then thermally treated using calcination
procedures.

[0047] Calcination temperature may range from 199° C. to
595° C. Calcination may occur for periods of time ranging from 0.5
to 5 hours, or more, to produce a catalytically active product especially
useful in hydrocarbon conversion processes.

[0048] The extrudate or particle may then be further loaded using a
technique such as impregnation, with a Group VIII metal to enhance the
hydrogenation function. It may be desirable to co-impregnate a modifying
metal and Group VIII metal at once, as disclosed in U.S. Pat. No.
4,094,821. The Group VIII metal is preferably nickel, platinum, palladium
or a combination thereof. After loading, the material can be calcined in
air or inert gas at temperatures from 260° C. to 482° C.

EXAMPLES

[0049] The following examples are given to illustrate the present
invention. It should be understood, however, that the invention is not to
be limited to the specific conditions or details described in these
examples.

Example 1

SSZ-32X Synthesis without Seeding

[0050] A reaction mixture for the synthesis of SSZ-32X was prepared by
adding in sequence to deionized water the following: 48% aqueous KOH (M),
0.47M N,N'-diisopropylimidazolium hydroxide (Q), and alumina-coated
silica sol 1SJ612 from Nalco (a version with 25 wt. % solids, a
SiO2/Al2O3 ratio of 35, and acetate as counter-ion). The
molar ratios of the reaction mixture components were as follows:

[0051] The reaction mixture was heated to 170° C. over an 8 hour
period and continuously stirred at 150 rpm for 135 hours at 170°
C.

[0052] The pH and the apparent viscosity of the reaction mixture were
monitored throughout the course of the reaction to determine the endpoint
of the reaction.

[0053] The measured viscosity was determined using standard techniques at
atmospheric pressure using a controlled stress rheometer equipped with a
cone and plate geometry. Hot slurry samples were taken hourly from the
autoclave during the zeolite synthesis process and carefully cooled
through a heat exchanger to sub-boiling temperatures before being
transferred to a closed container to minimize compositional changes from
vapor losses. The sample in the closed container was actively cooled to
about 25° C. The same sample may also be used for measuring the
viscosity shear rate index and the pH.

[0054] Each cooled slurry sample was mixed or shaken prior to loading on
the rheometer plate to ensure sample homogeneity, and the homogeneity of
the sample was maintained after loading by subjecting the sample to a
preliminary shear rate of 1000 s-1 for at least 30 s in order to
equilibrate the mixture at 25.0° C. Thereafter, each sample was
subjected to shear rates of 100 s-1, 200 s-1, 500 s-1, and
1000 s-1 at 25.0° C., and the corresponding shear stress
values needed to maintain those shear rates was recorded. The "measured
viscosity" of each sample was then determined by dividing the measured
shear stress by its corresponding shear rate.

[0055] The reaction endpoint was realized at a reaction time (at
temperature) of about 135 hours.

[0056] The product was determined via powder XRD analysis to be SSZ-32X.

[0057] The reaction time for synthesis of SSZ-32X can be considerably
shortened by the inclusion of seed crystals in the reaction mixture.

Example 2

SSZ-32X Synthesis with Seeding

[0058] A reaction mixture for the synthesis of SSZ-32X was prepared by
adding the same components as in Example 1, except SSZ-32X seeds (3.5 wt.
% based on the SiO2 content) were included in the reaction mixture.
The molar ratios of the reaction mixture components were as follows:

[0059] The reaction mixture was heated to 170° C. over an 8 hour
period and continuously stirred at 150 rpm for about 65 hours at
170° C.

[0060] The pH and the apparent viscosity of the reaction mixture were
monitored throughout the course of the reaction to determine the endpoint
of the reaction. The reaction endpoint was realized at a reaction time
(at temperature) of about 65 hours (see FIG. 1).

[0061] The zeolite sample was calcined to 595° C. and ion-exchanged
to the ammonium form as described in U.S. Pat. No. 7,390,763. The sample
was pre-heated to 450° C. to remove ammonia before the micropore
volume was determined according to ASTM D4365. The product had a
micropore volume of 0.034 cc/g. In contrast, standard SSZ-32 has a
micropore volume of about 0.06 cc/g.

[0062] The product was confirmed via powder XRD analysis to be SSZ-32X.

Example 3

SSZ-32X Synthesis with Seeding

[0063] A reaction mixture for the synthesis of SSZ-32X was prepared by
adding the same components as in Example 1, except SSZ-32X seeds (3.15 wt
% based on the SiO2 content) were included in the reaction mixture.
Seed crystals were obtained from a prior SSZ-32X preparation, see, for
example, Example 1. The molar ratios of the reaction mixture components
were as follows:

[0064] The reaction mixture was heated to 170° C. over an 8 hour
period and continuously stirred at 150 rpm for about 65 hours at
170° C.

[0065] The pH and the apparent viscosity of the reaction mixture were
monitored throughout the course of the reaction to determine the endpoint
of the reaction. The reaction endpoint was realized at a reaction time
(at temperature) of about 65 hours.

[0066] Analysis showed that the product had a SiO2/Al2O3
molar ratio of 29. The product was confirmed by powder XRD analysis to be
SSZ-32X. The product had a micropore volume of 0.035 cc/g as determined
by ASTM D4365.

Example 4

SSZ-32X Synthesis Via a Two-Temperature Method

[0067] Another sample of SSZ-32X was synthesized by adding the same
components as in Example 2, except that the reaction mixture was heated
to a higher initial temperature for a period of time. Seed crystals were
obtained from a prior SSZ-32X preparation, see, for example, Example 1.
The molar ratios of the reaction mixture components were as follows:

[0068] The reaction mixture was heated to 180° C. over an 8 hour
period and continuously stirred at 150 rpm for 39 hours at 180° C.

[0069] The pH and the apparent viscosity of the reaction mixture were
monitored throughout the course of the reaction to determine the endpoint
of the reaction. The reaction mixture was then allowed to cool to
170° C. over 1 hour and then held at 170° C. for 7.8 hours
at which time the reaction endpoint had been reached.

[0070] The product was determined via powder XRD analysis to be SSZ-32X.

[0071] In a concern that the products of the invention might be a mix of
small crystals and considerable amorphous material, the product of
Example 4 was analyzed by Transmission Electron Microscopy (TEM). Methods
for TEM measurement are disclosed by A. W. Burton et al. in Microporous
Mesoporous Mater. 117, 75-90, 2009. The microscopy work demonstrated that
the product was quite uniformly small crystals of SSZ-32 (the product was
SSZ-32X) with very little evidence of amorphous material. TEM
measurements showed elongated crystals with an average length of about 16
nanometers and an average width of about 8 nanometers. By contrast,
standard SSZ-32 crystals are elongate with an average length of about 170
nanometers.

Example 5

SSZ-32X Synthesis Via Concentrated Method

[0072] Another sample of SSZ-32X was synthesized by adding the same
components as in Example 2 except that the deionized water was eliminated
to provide a more concentrated reaction mixture. Seed crystals were
obtained from a prior SSZ-32X preparation, see, for example, Example 1.
The molar ratios of the reaction mixture components were as follows:

[0073] The reaction mixture was heated to 170° C. over an 8 hour
period and continuously stirred at 150 rpm for 65 hours at 170° C.

[0074] The pH and the apparent viscosity of the reaction mixture were
monitored throughout the course of the reaction to determine the endpoint
of the reaction. The reaction endpoint was realized at a reaction time
(at temperature) of about 65 hours.

[0075] The product was determined via powder XRD analysis to be SSZ-32X.
TEM measurements showed elongated crystals with an average length of
about 17 nanometers and an average width of about 9 nanometers.

Example 6

Over-Crystallized SSZ-32X

[0076] A reaction mixture for the synthesis of SSZ-32X was prepared by
adding the same components as in Example 1, except SSZ-32X seeds (3.15
wt. % based on the SiO2 content) were included in the reaction
mixture. The molar ratios of the reaction mixture components were as
follows:

[0077] The reaction mixture was heated to 170° C. over an 8 hour
period and continuously stirred at 150 rpm for about 90 hours at
170° C.

[0078] The pH and the apparent viscosity of the reaction mixture were
monitored throughout the course of the reaction to determine the endpoint
of the reaction. The reaction endpoint was realized at a reaction time
(at temperature) of about 65 hours but the reaction was allowed to
continue for 25 additional hours past the determined endpoint to provide
over-crystallized SSZ-32X.

[0079] The product was determined via powder XRD analysis to be SSZ-32X.
The product, as determined TEM measurements, showed elongated crystals
with an average length of at least 43 nanometers and an average width of
at least 23 nanometers. Particularly desirable SSZ-32X crystals typically
have a crystallite size of no more than 40 nanometers.

[0080] For the purposes of this specification and appended claims, unless
otherwise indicated, all numbers expressing quantities, percentages or
proportions, and other numerical values used in the specification and
claims, are to be understood as being modified in all instances by the
term "about." Accordingly, unless indicated to the contrary, the
numerical parameters set forth in the following specification and
attached claims are approximations that can vary depending upon the
desired properties sought to be obtained by the present invention. It is
noted that, as used in this specification and the appended claims, the
singular forms "a," "an," and "the," include plural references unless
expressly and unequivocally limited to one reference. As used herein, the
term "include" and its grammatical variants are intended to be
non-limiting, such that recitation of items in a list is not to the
exclusion of other like items that can be substituted or added to the
listed items.

[0081] This written description uses examples to disclose the invention,
including the best mode, and also to enable any person skilled in the art
to make and use the invention. The patentable scope is defined by the
claims, and can include other examples that occur to those skilled in the
art. Such other examples are intended to be within the scope of the
claims if they have structural elements that do not differ from the
literal language of the claims, or if they include equivalent structural
elements with insubstantial differences from the literal languages of the
claims. To an extent not inconsistent herewith, all citations referred
herein are hereby incorporated by reference.